DESCRIPTION (Applicant's abstract): Breast cancer is one of the greatest threats to the health and well being of every woman. The detection, diagnosis, and treatment of this cancer is a major initiative in the United States. HER-2/neu overexpression is associated with breast cancer prognosis and response to chemotherapy or endocrine therapy. Her-2/neu overexpression/amplification can be assessed by different techniques, including immunohistochemistry, fluorescence in situ hybridization (FISH), and various genetic hybridizations. However, the assessment of this important prognostic maker is hampered by the lack of standardization of the various methodologies, scoring systems, and widely accepted controls. Moreover, there is no general data bank where the laboratories can post their results for either comparison with other laboratories or evaluation of self-performance. We suggest that, if uniform, cell culture-based control slides were used by individual laboratories, this would ensure proper quality control over time and allow correlation of results with other laboratories. Potentially such controls could be used as standards and calibrators for quantitative immunohistochemistry, fluorescence in situ hybridization, and various genetic hybridization procedures. The specific aims of this proposal are : 1) To prepare cell culture-based controls for immunohistochemical detection of Her-2/neu protein; 2) To prepare cell culture-based controls for fluorescence in situ hybridization (FISH) analysis of the Her-2/neu oncogene; 3) To prepare cell culture-based controls for polymerase chain reaction (PCR), Southern blots, Northern blots, and Western blot hybridization analysis of the Her-2/neu oncogene. PROPOSED COMMERCIAL APPLICATIONS: Uniform and replenishable control slides prepared from cultured cells can be marketed as standards and calibrators for quantitative immunohistochemistry, fluorescence in situ hybridization, and various genetic hybridizations in diagnostic laboratories around the world. These controls ensure proper quality control over time and to allow correlation of results among multiple laboratories.